Introduction and objectives COPD patients have been shown to have a higher incidence of MI and stroke, than the general.1 There is also evidence that the risk of MI and stroke, in COPD patients, increases following an exacerbation.2 However, the association appears stronger between COPD exacerbations and MI, than it does between COPD exacerbations and stroke.1,2 We hypothesise that COPD patients, who are frequent exacerbators, have a higher stroke risk, than those who are infrequent exacerbators, even when stable.
Methods COPD patients, with a first stroke between 2004 and 2013, were identified in the UK CPRD database, as cases. Controls, were COPD patients, registered in the CPRD database, matched 3:1, to cases on age, sex and GP practice. We defined “frequent exacerbators” as COPD patients, with ≥ 2 exacerbations, resulting in treatment, per year and “infrequent exacerbators” as ≤1 exacerbation, per year. We also grouped exposure into four levels; 0, 1, 2 or ≥3 exacerbations, per year, to allow an analysis for trend between exacerbation number and stroke. A subgroup analysis of the association between exacerbation frequency and stroke type (ischaemic/ haemorrhagic or TIA) was also carried out. Conditional logistic regression was used for the analyses.
Results There were 6,441 cases and 19,323 controls. No difference was found in odds of stroke, comparing frequent and infrequent exacerbators (adjusted‡ OR 0.95, 95% CI 0.89–1.01, p = 0.09), or in the odds for stroke of any type. However, there was a reduction in odds of stroke associated with increased number of exacerbations, per year, with evidence for a linear trend (p = 0.002) (see Table 1.)
Conclusion These findings do not support the hypothesis that exacerbations in COPD are associated with increased stroke risk and warrant further investigation.
‡Adjusted for age, sex, general practice, smoking status, family history, hypertension, heart failure, CABG, angina, B-blocker and Calcium channel blocker.
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Donaldson, GC, et al. Increased risk of myocardial infarction and stroke following exacerbation of COPD. Chest, 2010:137(5): p. 1091-7